The present invention relates to a method and an apparatus for filling a liquid crystal material to liquid crystal panels (panel cells).
A dipping method has been employed to inject and fill a liquid crystal material to liquid crystal panels heretofore.
A conventional liquid crystal filling apparatus is shown in FIG. 4. A plurality of liquid crystal panels 1 are accommodated in a filling jig cassette 18 of the apparatus with injection ports 1a thereof faced down. A constant amount of a liquid crystal material 11 is stored in a liquid crystal pot 20. Both the filling jig cassette 18 and the liquid crystal pot 20 are placed in a vacuum chamber 19 so that the liquid crystal panels 1 are held out of touch with the liquid crystal material 11.
The vacuum chamber 19 is first reduced to at least about 10.sup.-3 to about 10.sup.-4 Torr, whereby air dissolved in the liquid crystal material 11 stored in the liquid crystal pot 20 is degassed. After the air in the liquid crystal material 11 is degassed sufficiently, the pot 20 is raised by an elevation device 17 and stopped at a position where lower parts of the liquid crystal panels 1 fully immersed in the pot.
Thereafter, N.sub.2 gas is introduced into the vacuum chamber 19, thereby to raise the chamber to an atmospheric pressure. In consequence, the liquid crystal material 11 in the pot 20 is pressed out by the pressure and injected/filled through the injection ports 1a to the liquid crystal panels kept still in the vacuum state inside. When all of the liquid crystal panels 1 are filled with the liquid crystal material 1, the liquid crystal pot 20 is lowered and the filling jig cassette 18 is taken out of the vacuum chamber 19. The filling is completed in this manner.
According to the above method and apparatus for filling the liquid crystal material to liquid crystal panels, a larger amount of the liquid crystal material than required should be stored beforehand in the pot so as to prevent the mixture of bubbles into the liquid crystal panels in the middle of the filling operation which would result from the lack of the liquid crystal material.
The liquid crystal material is contaminated and turned unusable after repeated filling operations. This is a waste of the expensive liquid crystal material.
Since the lower ends of the liquid crystal panels after the filling operation are totally wet with the liquid crystal material, the liquid crystal panels should be swabbed and cleaned afterwards, which requires a significant amount of time and cost.